Toxic spray compound



Patented Oct. 6, 1936 UNITED STATES TOXIC SPRAY COMPOUND Frank F. Lindstaedt, Oakland, Calif.

No Drawing. Application June 13, 1934, Serial'No. 730,470

3 Claims.

As is well known, oils, such as hydrocarbon oil,

are used extensively for horticultural parasiticidal purposes owing to the highly active nature thereof and the rapidity with which such activity is instigated and distributed. Such an oil is particularly effective where ready access to the spiracles of the parasites is aiforded since in this manner smothering or asphyxiation may be quickly accomplished. In the case, however, of parasitical formations such as red scale, the hydrocarbon oil is of itself only fairly efiective. As a matter of fact tests with hydrocarbon oil alone, at one half of one per cent strength in an aqueous carrier, show that the average kill is less than fifty per cent, the tests having been made with oil of about 45 Saybolt' viscosity. Of course the proportion of the hydrocarbon oil could be increased to insure an absolute kill, but it will be understood that such a step would damage the plant to an extent out of all proportion to the benefit received. A consideration of the results in the foregoing makes clear that the hydrocarbon oil'at a reasonably safe strength to the plant is highly eifective for killing certain members of the parasites but is entirely ineffectual for killing the remainder. I have discovered that practically all of the parasital life reappearing on the plant after an application of the hydrocarbon oil is that of newly matured members, and this has convinced me that the hydrocarbon oil is ineifective in killing the young. That this is reasonable is evidenced by the fact that, as is well known, the female parasite carries its young completely enclosed in its sack, and frequently the young even while in such sack will flourish and mature after the parent has died. Naturally, with such sack closed the young are to a large extent immune from the effect of the hydrocarbon oil. It has therefore occurred to me that a much more efiective kill of the parasites may be accomplished by adding to or supplanting part of the hydrocarbon oil content in the spray mixture with a quantity of a toxic oil which would be slow acting and reach and maintain over a relatively long period an eifective degree of activity upon dissipation of the energy of the hydrocarbon oil. In this way the killing of the adult parasites will be effected by the hydrocarbon oil and then the killing of the young will be assured when in the course of time and during activity of the slow acting toxic substance the maturing young will force open the sack and become exposed. I have discovered that remarkable results are obtained when. for the slow acting toxic aforesaid there is used one or more members of the oils ,of the Flacourtiacede (or Bimaceae) which contain glycerides or. the chaulmoogric group of acids. Good examples of such oils are those derived from the species of the Taraktogenos kurzii, the Hydnocarpus, the Oncoba, and the Carpotroche brasiliensis. Most preferable of the oils is Gynocdzidiq odorata or, as it is more commonly called, chaulmoogra, since it contains in abundance the chaulmoogric and hydnocarpic glycerides which are comparatively highly toxic as well as of high molecular weight. So potent is the combination of the hydrocarbon oil and the chaulmoogra oil that almost a one-hundred per cent kill of red scale parasites may be obtained by use of the aqueous carrier of but from one half of one per cent to two and one-half per cent of the mixture of the hydrocarbon and chaulmoogra oils. The proportion of the chaulmoogra oil required is exceedingly small, since in most cases but from one to five per cent thereof in the hydrocarbon oil is sumcient. The hydrocarbon oil generally used ranges from 35 to Saybolt viscosity.

I claim:

1. A toxic spray compound comprising a mixture of hydrocarbon oil and chaulmoogra oil.

2. A toxic spray compound comprising a mixture of hydrocarbon oil and chaulmoogra oil in the proportion by weightci approximately from one to five per cent of the chaulmoogra oil in the hydrocarbon oil.

3. A toxic spray compound mixed withan aqxeous carrier comprising, approximately ifrom one half of one per cent to two and one-half per cent in said carrier of a mixture oi approximately from one to five per cent oi/chaulmoogra oil in hydrocarbon oil of between approximately thirtyflve and one hundred and ten Saybolt viscosity.

. FRANK F. LINDSTAEDT. 

